In order for a target tracking system to lock onto a given target, a sensor must first locate/detect the target to allow the tracking system to follow the target's movement with respect to the tracking system so that the tracking system may predict where the target will be in the immediate future. The first step of this procedure, the locating phase, currently involves detecting an object within a window, and determining the position of the object. It is the target position that is tracked by the system.
Tracking a target presents certain problems associated with the target environment. The first problem is that a track is easily corrupted by other targets, e.g., ships, planes, land and clutter, entering a track window. This problem causes a position error in the tracked target's position calculation. The position error directly affects the forecast position, velocity and position uncertainty estimates for the track. With increased position error, a larger window is required around the target's forecast position, thereby increasing the probability that the target track will be corrupted by other targets. In addition, tracking becomes increasingly difficult when a weak target is being tracked around stronger targets.
Another deficiency with current target tracking systems is their difficulty in differentiating between two closely situated targets. Tracking systems tend to mistakenly characterize two targets as one and attempt to track the combination. For example, two ships traveling parallel to one another may be detected and tracked as one target. Moreover, while attempting to track a target with current systems, additional targets that enter the window reduce the accuracy of the track. Additionally, the ability to determine initial target track is greatly inhibited when starting a track window around multiple targets.